motormike40

I failed emissions yesterday my Nox ppm was doubled what was allowed. I'm running a chipped p28 on a turbo b18c1 with a cat. The only thing I could think of could be the tune, it was tuned on the street with a wideband, I don't know what the af we tuned it was at. Any ideas to why there's too much nitrogen coming from my car?

96leatherhatch

Was the cat hot? I have passed emissions several times by running on three cylinders....unplug the injector and plug wire

motormike40

Yea, It was warm. I heard about unplugging an injector. I also have a dyno tune of a b16 with my setup that I could swap in and retest it and hope for the best.

VtecCarHauler

try e85

Bseriescivic5

run your gas down pretty low and drop in 2-3 bottles of isopropel alcohol.

fmfkid250

1.Advance your timing 30 more Deg,
2.Go have someone fix the tune at idle and 2500rpm. (lean as hell+mad timing)

92TypeR

If you were on the safe side on CO and HC output, add more fuel. Assuming you already have a functioning catalytic converter.

NOx increases with combustion temperatures. Run on the rich side, NOx will decrease. You do not need much more fuel, and do not go overboard or you will fail on HC and CO output.

irishflame27

i agree, without a EGR system NOx increase, adding more fuel will lower combustion temps, which in turn will lower your NOx